Flush
Your Jeep's Radiator

This write-up is meant to
assist you in changing your Jeep's antifreeze. While you're at it, you
can also flush the radiator. I always find some sort of sediment when I
drain my radiator, so I take the extra steps of flushing the entire
system while I'm at it.

Before you begin, you should inspect the radiator cap. Replace the cap
if the pressure gasket is worn, torn, or swollen. Look for white spots
around the radiator fill neck. These indicate the cap is leaking. Also,
inspect the hoses. Replace any hoses that are cracked, bulging, or feel
brittle when squeezed.

Before
we begin, a couple of
warnings:

Never
open the cylinder block drain plugs, radiator cap or open the petcock
while the engine is hot or the cooling system is under pressure. You're
likely to burn yourself. Also, antifreeze is poisonous. Children and
animals are attracted to it due to the color and odor.
If you suspect a child has consumed any antifreeze, immediately call
911 or your local poison control center.

Begin
by finding a sealable
container large enough to collect the used antifreeze. Position it
under the
petcock which is located on the bottom of the radiator. On mine, the
petcock
is located on the passenger side, but the location might vary depending
on the source of your radiator (OEM vs. aftermarket). The photo to the
left is the petcock. It's opened by twisting the plastic tab.
Remember, it's plastic, so don't use too much force on it. Also, I
apologize for the poor quality photo, but I was laying on my back while
playing Ansel Adams.

After the radiator has drained, open
the radiator cap. Move your bucket
under the engine and remove drain plug on the left rear side of the
2.5L engine block or the coolant temperature sensor or drain plug on
the left side of the 4.0L engine block (image below).

If you're
flushing the system, follow
these steps or the directions on any radiator flushing products you
buy. Otherwise, you can skip this section and refill the system.

Once the coolant has drained,
tighten the petcock and any plugs
or
sensors you removed. Refill the radiator with water. Turn on the
Jeep's heater and run the engine until the thermostat opens (the upper
radiator hose will become hot). Repeat several times until the water
runs clear allowing the engine
to cool each time before opening the petcock to drain the radiator.

Once, the water runs clear,
determine the capacity of your radiator and fill to the top with a
50/50 mix of antifreeze and
distilled water. Do not use tap water - your body might need the
minerals, but your engine doesn't! Leave the radiator cap off to bleed
any air from the system. Start your Jeep and allow it to run until the
thermostat opens. As it runs, the coolant level should drop. This is
normal as the system bleeds any air pockets out of the system. Refill
the radiator and check for any leaks. After the engine has cooled, add
coolant to the overflow tank.
Due to thermal expansion, you shouldn't add coolant when the engine is
warm.

Dispose of your used antifreeze and
flushed water appropriately. DO
NOT pour it into the gutter or down a storm drain. Check with
your local water district or garbage company to determine the
appropriate method of recycling used antifreeze. Good luck!